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Old 12 January 2018, 13:00   #1
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Merc F150 some real life figures

Looking for some real life experiences with this engine.

I've plugged the figures into "quicksilver prop calculator" and it looks a if I'm going to be rev-ing to 5600 and at 41mph, going slower than I am just now with my Honda 130hp rev-ing at 5300 doing 43mph.

I'm currently running with a 20" Lazer II and being recommended a 19" for the Merc.
Looking at the difference in gear ratios Honda 2:1, Merc 1.92:1 I'd have expected exactly the same speed and revs with each but that's not what the calculator's telling me.?

Bottom line.....don't believe the calculator and I'm trying to come up with the right prop to order with the engine. My inclination is to keep the one I've got and go for a 21" with the new engine and I think it should be good for 47/48mph.

Your thoughts and experiences welcomed.
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Old 12 January 2018, 13:09   #2
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I'd certainly look at the Rev4 prop, not the best if speed is your thang, but one of the best props I've ever had on a RIB.
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Old 12 January 2018, 13:54   #3
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https://www.mercurymarine.com/en-gb/...units=imperial
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Old 12 January 2018, 14:02   #4
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Quote:
Originally Posted by Pikey Dave View Post
I'd certainly look at the Rev4 prop, not the best if speed is your thang, but one of the best props I've ever had on a RIB.
Skiing, cruising and top end I've never had any issues with the three blade Laser II, so someone would have to convince me of some kind of substantial gain or benefit to justify the extra cost of a 4/5 blade.

The dealer will throw in a prop included in the price but he's not going to cough for a Rev4.

I know the "hole shot" would probably be a bit better but even with the 130 Honda and 20" Laser, "deep starting" two skiers is effortless.

My main use is cruising, fairly long distance. maybe 80 to 100 miles in a day so I err on the "coarse side" as that keeps the noise down, seems to give best economy and top end for those idiot moments.
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Old 12 January 2018, 14:18   #5
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Well I put the Merc 150 on the rib three years ago and matched it with merc's 19" Enertia prop. Must say as one who only cruises I find it spot on.
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Old 12 January 2018, 14:41   #6
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at 47/48 kts how am I gonna keep up
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Old 12 January 2018, 14:50   #7
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Ain't no way it'll be 47 or 48 knots....mph yes.

Just a thought, maybe these new eco props are strong on pitch which would cause the info not adding up.

Ken at prop God's seems to be the goto person for prop info. His info is here, maybe worth a search herehttp://www.propgods.com/Content2/Default.aspx
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Old 12 January 2018, 15:01   #8
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Yeh.
It's looking like maybe keep my 20" and go for a 19" with the engine.
Do you know what your max speed and revs are with the 19" Jambo?
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Old 12 January 2018, 15:09   #9
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A quote from Ken at prop God's....."the ECO is a very large propeller and its strong on pitch"

There is a decent chance then this 19 and your 20 will be similar rpm wise. It isn't looking likely you will be able to spin an eco 21 for example.

Why don't you skip the prop and run your one first then get whatever sent later?
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Old 12 January 2018, 15:32   #10
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Quote:
Originally Posted by dubrus View Post
A quote from Ken at prop God's....."the ECO is a very large propeller and its strong on pitch"

There is a decent chance then this 19 and your 20 will be similar rpm wise. It isn't looking likely you will be able to spin an eco 21 for example.

Why don't you skip the prop and run your one first then get whatever sent later?
I'm looking at the ZPro650 test and thinking the boat is a pretty close match, his max revs at 5880 is actually over spec (5800) and that's with an 18 pitch.
So...19inch would be enough to push the revs back into spec Maybe 5600-5700 without compromising the top end significantly.
As you say, the 21" is probably going to be too coarse so as I've got a 20", the logical pick would be the 19" and in the unlikely event that's too much for skiing I've still got an "as-new" 18" black max in the shed.
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